Asteroids crashing into the ocean could have helped create the ingredients for life, scientists say.
By firing different materials together using a propellant gun, they found that amino acids could form when meteorites crash into the water.
That in turn could have helped bring the molecules that helped form life onto Earth – as well as potentially onto Mars, the researchers say.
Scientists have proposed two explanations for the arrival of the building blocks of life on Earth: either "extraterrestrial delivery", when they are brought on meteorites, or forming here on Earth.
The new research points to the former, the scientists from a range of Japanese institutions who conducted the study found.
The study saw researchers simulate the reactions that would happen when a meteorite crashes into the ocean. They did so by firing carbon dioxide, nitrogen, water, and iron together, using a propellant gun in a laboratory.
As they did so, they found that amino acids such as glycine and alanine. Such amino acids are key constituents of proteins, which in turn catalyse the kinds of biological reactions that form life.
Because scientists believe that Mars once had an ocean of its own, the same process could once have happened on the red planet, they speculate.